Electrical switching apparatus



April. 22, 1930. 'DUWE 1,755,689

ELECTRICAL SWITCHING APPARATUS Filed Jan. 25, 1928 Inven far Patented Apr. 22, 1930 UNITED STATES PA! ur oFFIc;

ASSIGNOB TO MASCHINENFABRIK A'UGS- ACOBPORATION OF GERMANY ELECTRICAL SWITCHING APPARATUS Application filed January 25,

kind consists in its simplest form of two con-' tact members included in the electric circuit for the motor, and adapted to be engagedwith and disengaged from each other to close or open the circuit.

Such simple switching apparatus, however, may be successfully employed only in very few cases. Among other things, such apparatus involves the disadvantage that the contact members may easily assume positions in which they are justabout contacting with each other, so that constant hammering of the two contacts occurs during the action of the regu-' lating device. To eliminate this disadvantage catch devices have been used in connection with the contacts. Such catch devices, however, involve another disadvantage, viz: that the adjusting force necessary contact members into contacting engagement must be relatively very large. Moreover, such an arrangement is unsuitable, where great accuracy of he operation of the regulatin device is required.

y invention consists in the construction of a switching apparatus which will be free of theaforementioned defects and disadvantages. For this purpose the operation of my new switching apparatus is based upon the frequently employed relay-principle, that is to say, the contact will be made by means of an outer force brought into action by the relatively small adjusting force of the regulating member. According to my invention the parts of the electrical circuit effecting the contact, that is the so-called contact members, are arranged upon a permanently rotating shaft being coupled therewith by means of friction couplings. For this purpose the contact devices each have two arms carrying blades or ratchets at then ends each arm being adapted to come in engagement with the free end of an operating lever mounted on a shaft actuated by the 0 device, n this way the contact devices will be for bringing the may be driv n by erating mechanism of a regulating 1928, Serial No. 249,325, and in Germany March 12, 1927.

prevented from rotating with their drivin shaft. The contact devices, on the other hand may be caused torotate with their shaft in order to make the desired electrical connections as soon as said operating lever is actuated by said operating mechanism.- In this manner the blades or ratchets'will come into and out of engagement with said levers according to the position of the latter. The contact device will make one half of a revolution, until the other of said two arms will again rest upon said lever so that further rotation of the contact device will be prevented. In this way the contacts will be closed and remain in closed condition, the contact device being now again at rest. Upon the rotation ofthe shaft being reversed which is operated by the regulating device, the blades provided on said arms will again be released and the'contact device again rotated by its shaft, thus opening the circuit and maintaining the same in open condition.

Upon the constantly rotating shaft there.

may be provided several contact devices side by side, said contact devices being each equipped with a pair of arms coming into alternate engagement with said levers which are actuated by the operating mechanism of the regulating device, so that it will be possible to arrange the switching apparatus for different modes of switching.

The accompanying drawing shows in a diagrammatic perspective View a switching apparatus constructed according to my invention. The switching apparatus-as shown is furthermore constructed to operate two electric motors both as to forward and rearward rotation, the entire switching operations being controlled by a single controlling or regulating member, e. g., a float.

Upon the constantly rotating shaft 1, which an electric motor, there are mounted four contact devices 2, 3, 4 and 5, each enclosed by a casing 6, 7, 8 and 9 respectively. The casings are mounted loosely on shaft 1, connections between said casings and the shaft, however, being provided in the form of friction couplings. The mode of operation described.

latter arms carrying the blades 22, 23, 24 and 25 respectively. p

The arms 18, 19,20 and 21 may rest with their blades 22,23, 24 and 25 upon the free apparatus.

end of the regulating levers 26, 27, 28 and 29 respectively, said free ends being constructed in the manner of pawls. These regulating levers 26, 27 28 and 29 are mounted on a common regulating shaft 30. As will be seen from the drawing, the pawls 31, 32, 33 and 34 provided on the free ends of the levers 26, 27 28 and 29 respectively are so dimensioned, that the blades 14, 15, 16 and 17 of the arms 10, 11, 12 and 13 will rest just on the left-hand side of said pawls, while the blades of the arms 18, 19, 20 and 21 will rest just on the right-hand end of said pawls, the levers 26, 27,28 and 29 being then in their central position as indicated in the drawing.

On the left-hand end of the shaft 30 there is provided another lever 35, the free end of which engages with the rod of the control This rod may for instance be connected with the float or other control member provided for the control of the contact apparatus and for imparting motion to all levers mounted on the shaft 30 either in lefthand or right-hand direction.

In proximity to the shaft 1 are positioned the contact springs 36, 37, 38 and 39 which will come in engagement with the contact members 2, 3, 4 and 5 respectively. Rotary motion is imparted to the casings, 6, 7, 8 and 9 by the constantly rotating shaft 1 in a manner shown in connection with casing 6, viz: by means of friction couplings, each friction coupling consisting of a hub 40 secured to the shaft 1 and friction blocks 41 and 42 forced outwardly by springs. These friction blocks are in sliding engagement with the interior wall of the casings and will impart rotation thereto, whenever the arms which are fixed on said casings are not engaging with the ends of the regulating levers 26, 27, 28 and 29.

It may be now assumed, that the lever 35 and therewith also the levers 26,27, 28 and 29 whichare mounted on the shaft 1 be turned towards the right in the figure,.this being due, for instance to the upward motion of a water-level and of a float operated thereby.

During this motion towards the right the blade 14 of the switch arm 10 will slide off the left-hand end of-the pawl 31 and shaft 1 therefore will rotate the casing6 by means of the friction coupling. The contact member 2 being also rotated will come in contacting engagement with the contact spring 36, thus closing the electric circuit which may, for instance, result in lifting the gate of'a weir in order to again lower the previously raised water-level.

During the rotation of casings 6, the blade 22 of the arm 18 will engage the pawl 31. of lever 26, the casing 6 being thereby prevented from further rotation. The contact between the contact member 2 and the contact spring 36 will therefore be temporarily maintained.

If .the motion produced by the switching operation has been sufficient, the direction of motion of the lever 35 and therewith of'the levers 26, 27, 28 and 29 will be reversedwhich in the case as assumed may be due to the downward motion of the float or other control member and the various levers will return to their normal positions. case, the blade 22, which had been resting on the right-hand endof the pawl 31 will slide off said pawl, so that casing 6 may now be further rotated whereby the contact between the contact member 2 and the contact spring 36 is interrupted and the electrical circuit for thedriving motor, for instance, the driving motor for the gate of a weir is opened. The blade 14 will now again engage the pawl 31 thus again establishing the original condition.

If during the first turn of the regulating shaft 30 the lever 35 is moved towards the left, casing 6 together with its contact member will remain at rest. On the other hand, the contact member 3 will come in engagement with the contact spring 37, the blade 23 of lever 19 having been disengaged from the right-hand end of pawl 32 of the lever 27, and, for instance, by means of proper electrical connections for the driving motor for the gate, a downward motion of the latter will be the result. The further course of the regulating operation will be similar to that which had previously been described.

The low casings 8 and 9 together with their contact members 4 and 5 may be actuated, if the effect of the switching operations which had been caused by the first two contact members 2 and 3 had not been sufficient, or if for some other reasons further switching operation are desired. In order to properly accompli sh this, this distance between the blades '16 and 25 and the ends'of the pawls 33 and 34 respectively is made greater than the respective distances at the pawls 31 and 32. The levers 12 and 21 will therefore be released only in case of a greater motion of the regulating levers 28 and 29. In a similar manner,

In that also further contact devices may be mounted upon the driving'shaft 1 and further regulating levers upon the regulating shaft 30.

From the above-given explanations it may be seen that the regulating device, for instance the float, needs only to ad'ust the a shaft 30 together with the severa levers mounted thereon, small forces being suflicient for this urpose. The switching operation roper W ich eventually may require a larger orce is performed by the shaft- 1. -Since a suflicient force isavailable here, all difliculties which may, arise in this respect are fully avoided. m I claim:

1. In electric switching apparatus, the combination with a control member, of .a shaft adapted to be rotated thereby, an operating lever mounted on said shaft, a continually rotating shaft, a contact member, a frics tion coupling intermediate said contact member and said second shaft, a contact spring to be engaged by said contact member, and two arms radially extending from said contact member in opposite directions, either being adapted to engage said operating lever, the arrangement being such t at upon the rocking of said first mentioned shaft said operating lever is moved thereby to a position'releasasingthe arm then in engagement with said operating lever allowing said contact member'to be moved by said continually rotating shaft to a new switching position and being held therein by the other arm.

2. In electric switching apparatus, the combination with a control member, of a shaft adapted to be rotated thereby, a lurality of operating levers mounted on sai shaft, a continually rotating shaft, contact members corresponding in number to said operating levers, friction couplings between said contact member and said second shaft, contact springs to be engagd by said contact members, each contact member having two 40 arms radially extending therefrom in opposite directions, being adagtedto engage said operatinglevers and of ifferent lengths to engage said levers at different points, the arrangement being such that upon the rotation of said first mentioned shaft'and the corresgonding movement of said operating levers, t e arms then in engagement therewith are released, emitting the corresponding contact mem ers to move to different switching positions, the different lengths of said arms permitting the switching operations to be effected'in predetermined succession.

In testimony'whereof I aflix m si ature.

' FRIEDRICH D 

